Photoreactive liquid crystal composition, display element, optical element, method for manufacturing display element, and method for manufacturing optical element

ABSTRACT

A photoreactive liquid crystal composition containing (A) a photoreactive polymer liquid crystal which includes a photoreactive side chain in which at least one type of reaction selected from (A-1) photocrosslinking and (A-2) photoisomerization occurs, and (B) a low molecular weight liquid crystal. An optical element or display element is formed having a liquid crystal cell including the photoreactive liquid crystal composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/115,554, filed on Jul. 29, 2016, which is a national stage patentapplication of international patent application PCT/JP2014/072697, filedon Aug. 29, 2014, the text of which is incorporated by reference, andclaims foreign priority to Japanese Patent Application No. 2014-016187,filed on Jan. 30, 2014, the entire content of which is incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to a photoreactive liquid crystalcomposition, a display element and an optical element comprised of thephotoreactive liquid crystal composition, and methods for manufacturinga display element and an optical element.

BACKGROUND ART

A current liquid crystal display element has used a liquid crystalalignment film which has been subjected to an alignment treatment inorder to make the liquid crystal uniformly aligned, except for someelements such as a polymer dispersed liquid crystal (PDLC) (Non-PatentLiterature 1). The alignment treatment of the liquid crystal alignmentfilm has had, after the liquid crystal alignment film is applied, aprocess generally called a rubbing treatment, that is, a process forrubbing a film surface with a roller having cloth wrapped around.However, since the process is the step of rubbing the film surfacephysically, scratches and/or shavings due to the rubbing processdeteriorate display performance of a liquid crystal display elementdisadvantageously. Further, this alignment treatment needs to go throughmany steps such as a liquid crystal alignment film formation step, aliquid crystal alignment treatment step, and a liquid crystal alignmentfilm cleaning step, thereby complicating the manufacturing process.

Therefore, in view of process and cost, it is largely advantageous tomanufacture a liquid crystal cell capable of controlling orientation ofa liquid crystal without the liquid crystal alignment film.

Meanwhile, a diffraction grating, which is capable of branch of a lightwave, conversion or a propagation direction, condensing dispersion, orthe like, has been widely used as a passive element in an opticalelectronics field such as optical recording or optical informationtransmission.

A typical manufacturing method is a method using a photoresist used forforming a semiconductor integrated circuit or the like. However, adiffraction element formed in this way has no optical anistropy, or doesnot easily form periodic optical anistropy controlled, and thus cannotcontrol, a polarization state. In order to control polarization, it isnecessary to control optical anisotropy highly, and to form a structurehaving periodicity. Therefore, for example, it has been proposed toutilize an axis-selective photoreaction of polyvinyl cinnamate (PVCi) orazobenzene capable of generating optical anisotropy simultaneously whenchange in a refractive index is caused by a photochemical reaction.

However, birefringence induced in the axis-selective photoreaction ofPVCi is as very small as 0.01. Also azobenzene, large birefringence isnot induced. Since characteristics are changed by an external field suchas heat or light, or since light absorption occurs in a visible region,it is difficult to apply PVCi or azobenzene to a passive optical device,which requires high stability.

More, in recent years, realization of a polarization control typediffraction element capable of controlling diffraction characteristicsby an electric field has been expected. It is disclosed (PatentLiterature 1) that an optical diffraction liquid crystal elementcharacterized by including a polymerization layer having a periodicallyvarying and fixed molecular orientation structure and a low molecularliquid crystal layer. If an orientation state of a liquid crystal can becontrolled arbitrarily in a liquid crystal bulk, various opticalelements, for example, a diffraction grating having a periodicorientation distribution, a lens, a mirror, and the like can be provided(Non-Patent Literature 2 or 3). However, in a case of the diffractiongrating of the structure, in forming a polymerization layer having amolecular orientation structure, it is necessary to perform an alignmenttreatment, and manufacturing of the diffraction grating is complicateddisadvantageously.

PRIOR ART DOCUMENT Patent Document

-   [Patent Document 1] JP-A-2006-20388.

Non-Patent Document

-   [Non-Patent Document 1] Liquid Crystal Handbook MARUZEN Company    Limited.-   [Non-Patent Document 2] S. Sato, Jpn. J. Appl. Phys. 18, 1679    (1979).-   [Non-Patent Document 3] T. Scharf, Polarized Light in Liquid    Crystals and Polymers (Wiley, 2007)

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

An object of the present invention is to provide an element,specifically a display element and an optical element, obtainedcontrolling orientation of a liquid crystal in a liquid crystal bulkwithout a liquid crystal alignment film, and/or to provide aphotoreactive liquid crystal composition for manufacturing the element.

Further, in addition to, or other than the above objects, an object ofthe present invention is to provide a method for manufacturing anelement obtained by controlling orientation of a liquid crystal in aliquid crystal bulk without a liquid crystal alignment film.

Means for Solving Problems

The present inventors have found the following inventions:

<1> A photoreactive liquid crystal composition comprising:

(A) a photoreactive polymer liquid crystal having a photoreactive sidechain, which causes at least one reaction selected from the groupconsisting of (A-1) photocrosslinking, and (A-2) photoisomerization; and

(B) a low molecular liquid crystal.

<2> In the above item <1>, the (A) photoreactive polymer liquid crystalmay comprise a photoreactive side chain, which causes the (A-1)photocrosslinking reaction.

<3> In the above item <1> or <2>, a weight ratio of the (A)photoreactive polymer liquid crystal and the (B) low molecular liquidcrystal ((A) photoreactive polymer liquid crystal: (B) low molecularliquid crystal) may be 0.1:99.9 to 20:80, preferably 0.5:99.5 to 15:85,more preferably 0.8:99.2 to 10:90.

<4> In any one of the above items <1> to <3>, the (A) photoreactivepolymer liquid crystal may comprise any one photoreactive side chainselected from the group consisting of the following formulae (1) to (6):

wherein A, B, and D each independently represents a single bond, —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —C═CH—CO—O—, or —O—CO—CH═CH—;

S represents an alkylene group having 1 to 12 carbon atoms, wherein ahydrogen atom bonded thereto may be replaced with a halogen group;

T represents a single bond or an alkylene group having 1 to 12 carbonatoms, wherein a hydrogen atom bonded thereto may be replaced with ahalogen group;

Y₁ represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalent,furan ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six rings selected therefrom are bonded through abonding group B, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ (wherein R₀ represents a hydrogenatom or an alkyl group having 1 to 5 carbon atoms), —NO₂, —CN,—CH═C(CN)₂, —CH═CH—CN, a halogen group, an alkyl group having 1 to 5carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;

Y₂ represents a group selected from the group consisting of a bivalentbenzene ring, a bivalent naphthalene ring, a bivalent biphenyl ring, abivalent furan ring, a bivalent pyrrole ring, a bivalent alicyclichydrocarbon having 5 to 8 carbon atoms and a combination thereof,wherein a hydrogen atom bonded thereto may be each independentlyreplaced with —NO₂, —CN, —CH═(CN)₂, —CH═CH—CN, a halogen group, an alkylgroup having 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5carbon atoms;

R represents a hydroxy group, an alkoxy group having 1 to 6 carbonatoms, or has the same definition as Y₁;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different;

Cou represents a coumarin-6-yl group or a coumarin-7-yl group, wherein ahydrogen atom bonded thereto may be each independently replaced with—NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, a halogen group, an alkyl group having1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;

one of q1 and q2 is 1, and another is 0;

q3 is 0 or 1;

P and Q each independently represents a group selected from the groupconsisting of a bivalent benzene ring, a bivalent naphthalene ring, abivalent biphenyl ring, a bivalent furan ring, a bivalent pyrrole ring,a bivalent alicyclic hydrocarbon having 5 to 8 carbon atoms and acombination thereof, in proviso that in a case where X is —CH═CH—CO—O—or —O—CO—CH═CH—, P or Q on a side to which —CH═CH— is bonded is anaromatic ring, in a case where the number of P is 2 or more, these Psmay be the same or different, and in a case where the number of Q is 2or more, these Qs may be the same or different;

l1 represents 0 or 1;

l2 represents an integer of 0 to 2;

in a case where both l1 and l2 are 0 and T is a single bond, A alsorepresents a single bond;

in a case where l1 is 1 and T is a single bond, B also represents asingle bond; and

H and I each independently represents a group selected from a bivalentbenzene ring, a bivalent naphthalene ring, a bivalent biphenyl ring, abivalent furan ring, a bivalent pyrrole ring and a combination thereof.

<5> In any one of the above items <1> to <4>, the (A) photoreactivepolymer liquid crystal may comprise any one photoreactive side chainselected from the group consisting of the following formulae (7) to(10):

wherein A, B, and D each independently represents a single bend, —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—;

-   -   Y₁ represents a ring selected from a monovalent benzene ring, a        monovalent naphthalene ring, a monovalent biphenyl ring, a        monovalent furan ring, a monovalent pyrrole ring and a        monovalent alicyclic hydrocarbon having 5 to 9 carbon atoms, or        a group in which the same or different two to six rings selected        therefrom are bonded through a bonding group B, wherein a        hydrogen atom bonded thereto may be each independently replaced        with —COOR₀ (wherein R₀ represents a hydrogen atom or an alkyl        group having 1 to 5 carbon atoms), —NO₂, —CN, —CH═C(CN)₂,        —CH═CH—CN, a halogen group, an alkyl group having 1 to 5 carbon        atoms, or an alkyloxy group having 1 to 5 carbon atoms;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, and each of m1 and m2 represents aninteger of 1 to 3;

n represents an integer of 0 to 12 (when n=0, B represents a singlebond);

Y₂ represents a group selected from the group consisting of a bivalentbenzene ring, a bivalent naphthalene ring, a bivalent biphenyl ring, abivalent furan ring, a bivalent pyrrole ring, a bivalent alicyclichydrocarbon having 5 to 8 carbon atoms and a combination thereof,wherein a hydrogen atom bonded thereto may be each independentlyreplaced with —NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, a halogen group, analkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to5 carbon atoms; and

R represents a hydroxy group, an alkoxy group having 1 to 6 carbonatoms, or has the same definition as Y₁.

<6> In any one of the above items <1> to <4>, the (A) photoreactivepolymer liquid crystal may comprise any one photoreactive side chainselected from the group consisting of the following formulae (11) to(13):

wherein A independently represents a single bond, —O—, —CH₂—, —COO—,—OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different;

l represents an integer of 1 to 12, m represents an integer of 0 to 2,and m1 represents an integer of 1 to 3; and

R represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six ring selected therefrom are bonded through abonding group B, wherein, a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ (wherein R₀ represents a hydrogenatom or an alkyl group having 1 to 5 carbon atoms), —NO₂, —CN,—CH═C(CN)₂, —CH═CH—CN a halogen group, an alkyl group having 1 to 5carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms, a hydroxygroup, or an alkoxy group having 1 to 6 carbon atoms.

<7> In any one of the above items <1> to <4>, the (A) photoreactivepolymer liquid crystal may comprise a photoreactive side chainrepresented by the following formula (14) or (15):

wherein A represents a single bond, —O—, —CH₂—, —COO—, —OCO—, —CONH—,—NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—;

Y₁ represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to rings selected therefrom are bonded through a bondinggroup B, wherein hydrogen atom bonded thereto may be each independentlyreplaced with —COOR₀ (wherein R₀ represents a hydrogen atom or an alkylgroup having 1 to 5 carbon atoms), —NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, ahalogen group, an alkyl group having 1 to 5 carbon atoms, or an alkyloxygroup having to 5 carbon atoms;

l represents an integer of 1 to 12, and each of m1 and m2 represents aninteger of 1 to 3.

<8> In any one of the above items <1> to <4>, the (A) photoreactivepolymer liquid crystal may comprise a photoreactive side chainrepresented by the following formula (16) or (17):

wherein A represents a single bond, —O—, —CH₂—, —COO—, —OCO—, —CONH—,—NH—CO—O, —CH═CH—CO—O—, or —O—CO—CH═CH—;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —CH≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different; and

l represents an integer of 1 to 12, and m represents an integer of 0 to2.

<9> in any one of the above items <1> to <4>, the (A) photoreactivepolymer liquid crystal may comprise a photoreactive side chainrepresented by the following formula (20):

wherein A represents a single bond, —O—, —CH₂—, —COO—, —OCO—, —CONH—,—NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—;

Y₁ represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six rings selected therefrom are bonded through abonding group B, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ (wherein R₀ represents a hydrogenatom or an alkyl group having 1 to 5 carbon atoms), —NO₂, —CN,—CH═C(CN)₂, —CH═CH—CN, a halogen group, an alkyl group having 1 to 5carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different; and

l represents an integer of 1 to 12, and m represents an integer of 0 to2.

<10> A display element comprised of a liquid crystal cell comprising thephotoreactive liquid crystal composition described in any one the aboveitems <1> to <9>.

<11> A display element comprised liquid crystal comprising thephotoreactive liquid crystal composition described in any one of theabove items <1> to <9>, wherein the (B) low molecular liquid crystal haspredetermined orientation in the crystal cell.

<12> An optical element comprised of a liquid crystal cell comprisingthe photoreactive liquid crystal composition described in any one theabove ems <1> to <9>.

<13> An optical element comprised of a liquid crystal cell comprisingthe photoreactive liquid crystal composition described in any one of theabove items <1> to <9>, wherein the (B) low molecular liquid crystal haspredetermined orientation in the liquid crystal cell.

<14> In the above item 12> or <13>, the predetermined orientation mayhave an orientation distribution in which orientation is differentdepending on the position of the optical element.

<15> A method for manufacturing an optical element, comprising the stepsof:

[I] filling a photoreactive liquid crystal composition comprising (A) aphotoreactive polymer liquid crystal having a photoreactive side chain,which cause, at least one reaction selected from the group consisting of(A-1) photocrosslinking and (A-2) photoisomerization; and (B) a lowmolecular liquid crystal; into a space formed between two transparentsubstrates disposed in parallel and apart from each other, to form aliquid crystal cell; and

[II] irradiating the liquid crystal cell obtained in the step [I] with apolarized ultraviolet ray from one of the two transparent substrates;

to form the optical element having a predetermined orientation of the(B) low molecular liquid crystal in the liquid crystal cell.

<16> In the step [II] of the above item <15>, setting a polarizing axisof a polarized ultraviolet ray with respect to a first position of theoptical element as a first axis, and setting a polarizing axis of apolarized ultraviolet ray with respect to a second position, which isdifferent from the first position of the optical element, as a secondaxis, which is different from the first axis, to form the opticalelement having the (B) low molecular liquid crystal with differentorientations between the first and second positions of the opticalelement.

<17> In the step [II] of the above item <15>, being subject tointerference exposure of the polarized ultraviolet ray, thepredetermined orientation may have an orientation distribution in whichorientation is different depending on the position of the opticalelement.

<18> A method for manufacturing a display element, comprising the stepsof:

[I] filling a photoreactive liquid crystal composition comprising (A) aphotoreactive polymer liquid crystal having a photoreactive side chain,which causes at least one reaction selected from the group consisting of(A-1) photocrosslinking and (A-2) photoisomerization; and (B) a lowmolecular liquid crystal; into a space formed between two transparentsubstrates disposed in parallel and apart from each other, to form aliquid crystal cell; and

[II] irradiating the liquid crystal cell obtained in the step [I] with apolarized ultraviolet ray from one of the two transparent substrates;

to form the display element having a predetermined orientation of the(B) low molecular liquid crystal in the liquid crystal cell.

Effects of the Invention

The present invention can provide an element, specifically a displayelement and an optical element, obtained by controlling orientation of aliquid crystal in a liquid crystal bulk without a liquid crystalalignment film, and/or to provide a photoreactive liquid crystalcomposition for manufacturing the element.

Further, in addition to, or other than the above effects, the presentinvention can provide a method for manufacturing an element obtained bycontrolling orientation, of a liquid crystal in a liquid crystal bulkwithout a liquid crystal alignment film.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an optical path diagram for performing hologramexposure in Example 1 and Comparative Example 1.

FIG. 2 illustrates a schematic diagram for measuring an intensity oftransmitted diffracted light of a liquid crystal cell obtained afterinterference exposure in Example 1 and Comparative Example 1.

FIG. 3 is a graph illustrating polarization azimuths dependence of adiffraction efficiency of the liquid crystal cell obtained afterinterference exposure.

FIG. 4 is a graph illustrating measurement results of a diffractionefficiency when a rectangular voltage of 1 kHz is applied.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

The present application provides an element, specifically a displayelement and an optical element, obtained by controlling orientation of aliquid crystal in a liquid crystal bulk without a liquid crystalalignment film, and/or provides a photoreactive liquid crystalcomposition for manufacturing the element.

In addition, the present application provides a method for manufacturingan element obtained by controlling orientation of a liquid crystal in aliquid crystal bulk without a liquid crystal alignment film.

The photoreactive liquid crystal composition, the element obtained bythe composition, and the method for manufacturing the element aredescribed hereinafter.

<Photoreactive Liquid Crystal Composition>

The photoreactive liquid crystal composition according to the presentinvention comprises (A) a photoreactive polymer liquid crystal having aphotoreactive side chain, which causes at least one reaction selectedfrom the group consisting of (A-1) photocrosslinking and (A-2)photoisomerization; and (B) a low molecular liquid crystal.

The photoreactive liquid crystal composition according to the presentinvention may consist of the (A) photoreactive polymer liquid crystaland the (B) low molecular liquid crystal, or may consist essentially of(A) and (B), including other components to such an extent thatproperties of (A) and (B) are net changed. Further, the photoreactiveliquid crystal composition according to the present invention maycomprise other components other than (A) or (B). <<(B) Low MolecularLiquid Crystal>>

The (B) low molecular liquid crystal included in the photoreactiveliquid crystal composition according to the present invention may use anematic liquid crystal, a ferroelectric liquid crystal or the like as itis, which have been conventionally used for a liquid crystal displayelement or the like.

Specific examples of the (B) low molecular liquid crystal may include,but are not limited to, cyanobiphenyls such as 4-cyano-4′-n-pentylbiphenyl, 4-cyano-4′-n-heptyloxy biphenyl or the like; cholesterylesters such as cholesteryl acetate, cholesteryl benzoate or the like;carbonate esters such as 4-carboxyphenyl ethyl carbonate,4-carboxyphenyl-n-butyl carbonate or the like; phenyl esters such asphenyl benzoate, biphenyl phthalate or the like; Schiff's bases such asbenzylidene-2-naphthylamine, 4′-n-butoxybenzylidene-4-acetyl aniline orthe like; benzidines such as N,N′-bisbenzylidene benzidine,p-dianisalbenzidine or the like; azoxybenzenes such as 4,4′-azoxydianisole, 4,4′-di-n-butoxy azoxybenzene or the like; liquid crystalssuch as phenylcyclohexyls, terphenyls, phenyl bicyclohexyls or the like,specifically indicated below.

<<(A) Photoreactive Polymer Liquid Crystal>>

The (A) photoreactive polymer liquid crystal (hereinafter, also referredto as “component (A)” simply) included in the photoreactive liquidcrystal composition according to the present invention is notparticularly limited as long as having a photoreactive side chain, whichcauses at least one reaction selected from the group consisting of the(A-1) photocrosslinking and the (A-2) photoisomerization.

Photoreactivity used herein means a property to cause one or both of the(A-1) photocrosslinking and the (A-2) photoisomerization.

The component (A) may have a side chain, which causes thephotocrosslinking reaction (A-1).

The component (A) is i) a polymer exhibiting liquid crystalline propertyin a predetermined temperature range and having a photoreactive sidechain.

The component (A) ii) may react by light in a wavelength range of 250 nmto 400 nm and may exhibit liquid crystalline property in a temperaturerange of 50 to 300° C.

The component (A) iii) may preferably have a photoreactive side chain toreact with light in a wavelength range of 250 nm to 400 nm, particularlywith a polarized ultraviolet ray.

The component (A) iv) may preferably have a mesogenic group in order toexhibit liquid crystalline property a temperature range of 50 to 300° C.

In the photoreactive liquid crystal composition according to the presentinvention, a weight ratio of the (A) photoreactive polymer liquidcrystal and the (B) low molecular liquid crystal ((A) photoreactivepolymer liquid crystal: (B) low molecular liquid crystal) may be from0.1:99.9 to 20:80, preferably from 0.5:99.5 to 15:85 and more preferablyfrom 0.8:99.2 to 10:90.

As described above, the component (A) has a photoreactive side chainhaving photoreactivity. The structure of the side chain is notparticularly limited, but causes a reaction indicated in the above (A-1)and/or (A-2), and preferably causes the (A-1) photocrosslinkingreaction. A structure to cause the (A-1) photocrosslinking reaction ispreferable because the structure after the reaction can hold orientationof the component (A) stably for a long time even when the structureafter the reaction is exposed to an external stress such as heat.

The structure of the side chain of the component (A) may preferablycomprise a rigid hemogenic component due to stable orientation of aliquid crystal.

Examples of the hemogenic component may include, but are not limited to,a biphenyl group, a terphenyl group, a phenyl cyclohexyl group, a phenylbenzoate group, an azobenzene group and the like.

The structure of a main chain of the component (A), for example, mayinclude, but is not limited to, at least one selected from the groupconsisting of radically polymerizable groups such as hydrocarbons,(meth)acrylates, itaconates, fumarates, maleates,α-methylene-γ-butyrolactones, styrenes, vinyl, maleimides, andnorbornenes and siloxanes.

The side chain of the component (A) may be at least one of the followingformulae (1) to (6):

wherein A, B, and D each independently represents a single bond, —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—;

S represents an alkylene group having 1 to 12 carbon atoms, wherein ahydrogen atom bonded thereto may be replaced with a halogen group;

T represents a single bond or an alkylene group having 1 to 12 carbonatoms, wherein a hydrogen atom bonded thereto may be replaced with ahalogen group;

Y₁ represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 9 carbon atoms, or represents a group in whichthe same or different two to six rings selected therefrom are bondedthrough a bonding group B, wherein a hydrogen atom bonded thereto may beeach independently replaced with —COOR₀ (wherein R₀ represents ahydrogen atom or an alkyl group having 1 to 5 carbon atoms), —NO₂, —CN,—CH═C(CN)₂, —CH═CH—CN, a halogen group, an alkyl group having 1 to 5carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;

Y₂ represents a group selected from the group consisting of a bivalentbenzene ring, a bivalent naphthalene ring, a bivalent biphenyl ring, abivalent furan ring, a bivalent pyrrole ring, a bivalent alicyclichydrocarbon having 5 to 8 carbon atoms and a combination thereof,wherein a hydrogen atom bonded thereto may be each independentlyreplaced with —NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, a halogen group, analkyl group having 1 to 5 carbon atoms, or an alkyloxy group having 1 to5 carbon atoms;

R represents a hydroxy group, an alkoxy group having 1 to 6 carbonatoms, or has the same definition as Y₁;

X represents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different;

Cou represents a coumarin-6-yl group or a coumarin-7-yl group, wherein ahydrogen atom bonded thereto may be each independently replaced with—NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, a halogen group, an alkyl group having1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbon atoms;

one of q1 and q2 is 1, and another is 0;

q3 is 0 or 1;

P and Q each independently represents a group selected from the groupconsisting of a bivalent benzene ring, a bivalent naphthalene ring, abivalent biphenyl ring, a bivalent furan ring, a bivalent pyrrole ring,a bivalent alicyclic hydrocarbon having 5 to 8 carbon atoms and acombination thereof, in proviso that in a case where X is —CH═CH—CO—O—or —O—CO—CH═CH—, P or Q on a side to which —CH═CH— is bonded is anaromatic ring, in a case where the number of P is 2 or more, these Psmay be the same or different, and in a case where the number of Q is 2or more, these Qs may be the same or different;

l1 represents 0 or 1;

l2 represents an integer of 0 to 2;

in a case where both l1 and l2 are 0 and T is a single bond, A alsorepresents a single bond;

in a case where l1 is 1 and T is a single bond, B also represents asingle bond; and

H and I each independently represents a group selected from a bivalentbenzene ring, a bivalent naphthalene ring, a bivalent biphenyl ring, abivalent furan ring, a bivalent pyrrole ring and a combination thereof.

The side chain may be any one photoreactive side chain selected from thegroup consisting of the following formulae (7) to (10):

wherein A, B, D, Y₁, X, Y₂, and R each has the same definition asmentioned above;

l represents an integer of 1 to 12;

m represents an integer of 0 to 2, and each of m1 and m2 represents aninteger of 1 to 3;

n represents an integer of 0 to 12 (when n=0, B represents a singlebond).

The side chain may be any one photoreactive side chain selected from thegroup consisting of the following formulae (11) to (13):

wherein A, X, l, m, m1 and R each has the same definition as mentionedabove.

The side chain may be a photoreactive side chain represented by thefollowing formula (14) or (15):

wherein A, Y₁, l, m1 and m2 each has the same definition as mentionedabove.

The side chain may be a photoreactive side chain represented by thefollowing formula (16) or (17):

wherein A, X, l and m each has the same definition as mentioned above.

The side chain may be a photoreactive side chain represented by thefollowing formula (20):

wherein A, Y₁, X, l and m each has the same definition as mentionedabove.

Further, the component (A) may comprise any one liquid crystalline sidechain selected from the group consisting of the following formulae (21)to (31). For example, in a case where a photoreactive side chain in thecomponent (A) does not have liquid crystalline property, or in a casewhere a main chain in the component (A) does not have liquid crystallineproperty, the component (A) may comprise any one liquid crystalline sidechain selected from the group consisting of the following formulae (21)to (31):

wherein A, B, q1 and q2 each has the same definition as mentioned above;

Y₃ represents a group selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent nitrogen-containing heterocyclic ring, and amonovalent alicyclic hydrocarbon having 5 to 8 carbon atoms, and acombination thereof, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —NO₂, —CN, a halogen group, an alkyl grouphaving 1 to 5 carbon atoms, or an alkyloxy group having 1 to 5 carbonatoms;

R₃ represents a hydrogen atom, —NO₂, —CN, —CH═C(CN)₂, —CH═CH—CN, ahalogen group, a monovalent benzene ring, a monovalent naphthalene ring,a monovalent biphenyl ring, a monovalent furan ring, a monovalentnitrogen-containing heterocyclic ring, a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, an alkyl group having 1 to 12carbon atoms, or an alkoxy group having 1 to 12 carbon atoms;

l represents an integer of 1 to 12; m represents an integer of 0 to 2,in proviso that all sum of m is 2 or more in the formula (23) or (24),that all sum of m is 1 or more in the formula (25) or (26);

m1, m2 and m3 independently represents an integer of 1 to 3;

R₂ represents a hydrogen atom, —NO₂, —CN, a halogen group, a monovalentbenzene ring, a monovalent naphthalene ring, a monovalent biphenyl ring,a monovalent furan ring, a monovalent nitrogen-containing heterocyclicring, and a monovalent alicyclic hydrocarbon having 5 to 8 carbon atoms,and an alkyl group or an alkyloxy group;

Z₁ and Z₂ independently represents a single bond, —CO—, —CH₂O—, —CH═N—,or —CF₂—.

<<Method for Manufacturing a Component (A)>>

The component (A) can be obtained by polymerizing a photoreactive sidechain monomer having the above photoreactive side chain, or in somecases, by copolymerizing the photoreactive side chain monomer and amonomer having the above liquid crystalline side chain.

[Photoreactive Side Chain Monomer]

The photoreactive side chain monomer used herein means a monomer whichcan form a polymer having a photoreactive side chain on a side chainportion of the polymer when the polymer is formed.

The photoreactive group in the side chain may be preferably thefollowing structure or a derivative thereof.

As a more specific example of the photoreactive side chain monomer, thephotoreactive side chain monomer preferably has a structure including apolymerizable group formed of at least one selected from the groupconsisting of radically polymerizable groups such as hydrocarbons,(meth)acrylates, itaconates, fumarates, maleates,α-methylene-γ-butyrolactone, styrenes, vinyls, maleimides, andnorbornenes and siloxanes, and a photoreactive side chain formed of atleast one of the above formulae (1) to (6), preferably, for example, aphotoreactive side chair, formed of at least one of the above formulae(7) to (10), a photoreactive side chain formed of at least one of theabove formulae (11) to (13), a photoreactive side chain represented bythe above formula (14) or (15), a photoreactive side chain representedby the above formula (16) or (17), or a photoreactive side chainrepresented by the above formula (20).

Examples of the photoreactive side chain monomer may include, but arenot limited to, compounds represented by the following formulae PRM-1 toPRM-11, wherein n represents an integer of 1 to 6, m represents aninteger of 0 to 4, X represents a hydrogen atom or a methyl group, Rrepresents a hydrogen atom, a linear or branched alkyl group or alkoxygroup having 1 to 3 carbon atoms, a halogen atom, a cyano group, or anitro group, R₁ to R₃ each independently represent a hydrogen atom, alinear or branched alkyl group or alkoxy group having 1 to 3 carbonatoms, or a halogen atom, and p represents an integer of 1 to 4.

[Liquid Crystalline Side Chain Monomer]

The liquid crystalline side chain monomer used herein means a monomersuch that, a polymer derived from the monomer exhibits liquidcrystalline property and the polymer can form a hemogenic group in aside chain portion.

A hemogenic group in the side chain may be a group which forms ahemogenic structure by a single compound such as biphenyls, phenylbenzoates or the like; or a group which forms a hemogenic structure byhydrogen bonding between side chains, such as benzoic acids. Preferably,the hemogenic group in the side chain may be the following structures:

As a more specific example of the liquid crystalline side chain monomer,the liquid crystalline side chain monomer preferably has a structurehaving a polymerizable group formed of at least one selected from thegroup consisting of radically polymerizable groups such as hydrocarbons,(meth)acrylates, itaconates, fumarates, maleates,α-methylene-γ-butyrolactone, styrenes, vinyls, maleimides, andnorbornenes and siloxanes, and a side chain formed of at least one ofthe above formulae (21) to (31).

Specific examples of the liquid crystalline side chain monomer mayinclude, but are not limited to, compounds represented by the followingformulae LCM-1 to LCM-9, wherein n represents an integer of 1 to 6, Xrepresents a hydrogen atom or a methyl group, R₄, R₆, and R₆₁ to R₆₃each independently represent a hydrogen atom, a linear or branched alkylgroup or alkoxy group having 1 to 3 carbon atoms, a halogen atom, acyano group, or a nitro group, R₅ represents a hydrogen atom, a linearor branched alkyl group having 1 to 6 carbon atoms.

The component (A) can be obtained by a polymerization reaction of theabove photoreactive side chain monomer exhibiting liquid crystallineproperty. Further, the component (A) can be obtained by copolymerizing aphotoreactive side chain monomer exhibiting no liquid crystallineproperty and a liquid crystalline side chain monomer or copolymerizing aphotoreactive side chain monomer exhibiting liquid crystalline propertyand a liquid crystalline side chain monomer. More, copolymerization withother monomer(s) can be performed in an extent not to impair an abilityto exhibit liquid crystalline property.

Examples of the other monomer(s) may include an industrially availableradically polymerizable monomer.

Specific examples of the other monomer(s) may include unsaturatedcarboxylic acids, acrylic acid ester compounds, methacrylic acid estercompounds, maleimide compounds, acrylonitriles, maleic anhydrides,styrene compounds, vinyl compounds and the like.

Specific examples of the unsaturated carboxylic acids may includeacrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acidand the like.

Examples of the acrylic acid ester compounds may include methylacrylate, ethyl acrylate, isopropyl acrylate, benzyl acrylate, naphthylacrylate, anthryl acrylate, anthrylmethyl acrylate, phenyl acrylate,2,2,2-trifluoroethyl acrylate, tert-butyl acrylate, cyclohexyl acrylate,isobornyl acrylate. 2-methoxyethyl acrylate, methoxy triethylene glycolacrylate, 2-ethoxyethyl acrylate, tetrahydrofurfuryl acrylate,3-methoxybutyl acrylate, 2-methyl-2-adamantyl acrylate,2-propyl-2-adamantyl acrylate, 8-methyl-8-tricyclodecyl acrylate,8-ethyl-8-tricyclodecyl acrylate and the like.

Examples of the methacrylic acid ester compounds may include methylmethacrylate, ethyl methacrylate, isopropyl methacrylate, benzylmethacrylate, naphthyl methacrylate, anthryl methacrylate, anthrylmethylmethacrylate, phenyl methacrylate, 2,2,2-trifluoroethyl methacrylate,tert-butyl methacrylate, cyclohexyl methacrylate, isobornylmethacrylate, 2-methoxyethyl methacrylate, methoxy triethylene glycolmethacrylate, 2-ethoxyethyl methacrylate, tetrahydrofurfurylmethacrylate, 3-methoxybutylmethacrylate, 2-methyl-2-adamantylmethacrylate, 2-propyl-2-adamantyl methacrylate,8-methyl-8-tricyclodecyl methacrylate, 8-ethyl-8-tricyclodecylmethacrylate and the like. (Meth)acrylate compounds each having a cyclicether group such as glycidyl (meth)acrylate, (3-methyl-3-oxetanyl)methyl (meth)acrylate, (3-ethyl-3-oxetanyl) methyl (meth)acrylate andthe like can be also used.

Examples of the vinyl compounds may include vinyl ether, methyl vinylether, benzyl vinyl ether, 2-hydroxyethyl vinyl ether, phenyl vinylether, propyl vinyl ether and the like.

Examples of the styrene compounds may include styrene, methyl styrene,chlorostyrene, bromostyrene and the like.

Examples of the maleimide compounds may include maleimide, N-methylmaleimide, N-phenyl maleimide, N-cyclohexyl maleimide and the like.

A method for manufacturing the side chain type polymer according to thepresent embodiment is not particularly limited, but a general methodused industrially can be used. Specifically, the side chain type polymercan be manufactured by cationic polymerization, radical polymerization,or anionic polymerization using a vinyl group of a liquid crystallineside chain monomer or a photoreactive side chain monomer. Among themethods, radical polymerization may be particularly preferable from aviewpoint of easiness of reaction control.

A polymerization initiator of radical polymerization may use a knowncompound such as a radical polymerization initiator, a reversibleaddition-fragmentation chain transfer (RAFT) polymerization reagent orthe like.

A radical thermal polymerization initiator is a compound, whichgenerates a radical by heating at a decomposition temperature or higher.Examples of the radical thermal polymerization initiator may includeketone peroxides (methyl ethyl ketone peroxide, cyclohexanone peroxideor the like), diacyl peroxides (acetyl peroxide, benzoyl peroxide or thelike), hydroperoxides (hydrogen peroxide, tert-butyl hydroperoxide,cumene hydroperoxide or the like), dialkyl peroxides (di-tert-butylperoxide, dicumyl peroxide, dilauroyl peroxide or the like), peroxyketals (dibutyl peroxy cyclohexane or the like), alkyl peresters (peroxyneo decanoic acid-tert-butyl ester, peroxy pivalic acid-tert-butylester, peroxy 2-ethyl cyclohexanoic acid-tert-amyl ester or the like),persulfate salts (potassium persulfate, sodium persulfate, ammoniumpersulfate or the like), and azo compounds (azobisisobutyronitrile,2,2′-di(2-hydroxyethyl) azobisisobutyronitrile or the like). Such aradical thermal polymerization initiator can be used singly or incombination of two or more thereof.

A radical photopolymerization initiator is not particularly limited aslong as being a compound, which initiates radical polymerization bylight irradiation. Examples of such radical photopolymerizationinitiator may include benzophenone, Michler's ketone,4,4′-bis(diethylamino) benzophenone, xanthone, thioxanthone, isopropylthioxanthone, 2,4-diethyl thioxanthone, 2-ethyl anthraquinone,acetophenone, 2-hydroxy-2-methyl propiophenone,2-hydroxy-2-methyl-4′-isopropyl propiophenone, 1-hydroxycyclohexylphenyl ketone, isopropyl benzoin ether, isobutyl benzoin ether,2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone,camphorquinone, benzanthrone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1, 4-dimethylamino ethyl benzoate,4-dimethylamino isoamyl benzoate, 4,4′-di(t-butylperoxy carbonyl)benzophenone, 3,4,4′-tri(t-butyl peroxy carbonyl) benzophenone,2,4,6-trimethylbenzoyl diphenyl phosphine oxide,2-(4′-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(3′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(2′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(2′-methoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(4′-pentyloxystyryl)-4,6-bis(trichloromethyl)-s-triazine,4-(p-N,N-di(ethoxycarbonylmethyl))-2,6-di(trichloromethyl)-s-triazine,1,3-bis(trichloromethyl)-5-(2′-chlorophenyl)-s-triazine,1,3-bis(trichloromethyl)-5-(4′-methoxyphenyl)-s-triazine,2-(p-dimethylaminostyryl) benzoxazole, 2-(p-dimethylaminostyryl)benzothiazole, 2-mercaptobenzothiazole, 3,3′-carbonyl bis(7-diethylamino coumarin),2-(o-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,3-(2-methyl-2-dimethylamino propionyl) carbazole,3,6-bis(2-methyl-2-morpholino propionyl)-9-n-dodecyl carbazole,i-hydroxycyclohexyl phenyl ketone,bis(5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrole-1-yl)-phenyl)titanium,3,3′,4,4′-tetra(t-butyl peroxycarbonyl)benzophenone,3,3′,4,4′-tetra(t-hexylperoxycarbonyl) benzophenone,3,3′-di(methoxycarbonyl)-4,4′-di(t-butylperoxy carbonyl)benzophenone,3,4′-di(methoxycarbonyl)-4,3′-di(t-butylperoxy carbonyl)benzophenone,4,4′-di(methoxycarbonyl)-3,3′-di(t-butylperoxy carbonyl)benzophenone,2-(3-methyl-3H-benzothiazol-2-ylidene)-1-naphthalen-2-yl-ethanone,2-(3-methyl-1,3-benzothiazole-2(3H)-ylidene)-1-(2-benzoyl) ethanone andthe like. These compounds can be used singly or in combination of two ormore compounds thereof.

A radical polymerization method is not particularly limited, butexamples thereof may include an emulsion polymerization method, asuspension polymerization method, a dispersion polymerization method, aprecipitation polymerization method, a bulk polymerization method, asolution polymerization method and the like.

An organic solvent used for a generation reaction of the component (A),specifically a polymerization reaction of the above monomer is notparticularly limited as long as a generated polymer can be dissolvedtherein. Specific examples thereof may include the following:

N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone,N-ethyl-2-pyrrolidone, N-methyl caprolactam, dimethyl sulfoxide,tetramethylurea, pyridine, dimethyl sulfone, hexamethyl sulfoxide,γ-butyrolactone, isopropyl alcohol, methoxymethyl pentanol, dipentene,ethyl amyl ketone, methyl nonyl ketone, methyl ethyl ketone, methylisoamyl ketone, methyl isopropyl ketone, methyl cellosolve, ethylcellosolve, methyl cellosolve acetate, ethyl cellosolve acetate, butylcarbitol, ethyl carbitol, ethylene glycol, ethylene glycol monoacetate,ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether,propylene glycol, propylene glycol monoacetate, propylene glycolmonomethyl ether, propylene glycol-tert-butyl ether, dipropylene glycolmonomethyl ether, diethylene glycol, diethylene glycol monoacetate,diethylene glycol dimethyl ether, dipropylene glycol monoacetatemonomethyl ether, dipropylene glycol monomethyl ether, dipropylene,glycol monoethyl ether, dipropylene glycol monoacetate monoethyl ether,dipropylene glycol monopropyl ether, dipropylene glycol monoacetatemonopropyl ether, 3-methyl-3-methoxybutyl acetate, tripropylene glycolmethyl ether, 3-methyl-3-methoxy butanol, diisopropyl ether, ethylisobutyl ether, diisobutylene, amyl acetate, butyl butyrate, butylether, diisobutyl ketone, methylcyclohexene, propyl ether, dihexylether, dioxane, n-hexane, n-pentane, n-octane, diethyl ether,cyclohexanone, ethylene carbonate, propylene carbonate, methyl lactate,ethyl lactate, methyl acetate, ethyl acetate, n-butyl acetate, propyleneglycol monoethyl ether acetate, methyl pyruvate, ethyl pyruvate, methyl3-methoxypropionate, methyl ethyl 3-ethoxypropionate, ethyl 3-methoxypropionate, 3-ethoxypropionic acid, 3-methoxypropionic acid, propyl3-methoxy propionate, butyl 3-methoxy propionate, diglyme,4-hydroxy-4-methyl-2-pentanone, 3-methoxy-N,N-dimethyl propanamide,3-ethoxy-N,N-dimethyl propanamide, 3-butoxy-N,N-dimethyl propanamide andthe like.

These organic solvents may be used singly or in mixture thereof.Further, even a solvent which does not dissolve a generated polymer maybe used within a range not to make the generated polymer precipitatewhile being mixed with the above organic solvents.

Oxygen in an organic solvent inhibits a polymerization reaction inradical polymerization. Therefore, an organic solvent which has beendegassed to a possible extent may be preferably used.

A polymerization temperature in radical polymerization may select anytemperature in a range of 30° C. to 150° C., but a temperature in arange of 50° C. to 100° C. may be preferable. A reaction can beperformed at any concentration. However, when the concentration is toolow, it is difficult to obtain a polymer having a high molecular weight.When the concentration is too high, the viscosity of a reaction liquidis too high, and uniform stirring is difficult. Therefore, the monomerconcentration is preferably from 1% by mass to 50% by mass, and morepreferably from 5% by mass to 30% by mass. The reaction may be performedat a high concentration in an initial stage of the reaction, andthereafter, an organic solvent can be added.

In the above radical polymerization reaction, a large ratio of a radicalpolymerization initiator with respect to a monomer makes a molecularweight of a polymer obtained small, and a small ratio of the radicalpolymerization initiator makes the molecular weight of the polymerobtained large. Therefore, the ratio of a radical initiator may bepreferably from 0.1 mol % to 10 mol % with respect to a monomer to bepolymerized. In polymerization, various monomer components, solvents,initiators and the like can be added.

[Recovery of Polymer]

In order to recover a product obtained by the above reaction, that is,the component (A) from a reaction solution, the reaction solution may beput into a poor solvent.

Examples of the poor solvent used for precipitation may includemethanol, acetone, hexane, heptane, butyl cellosolve, heptane, methylethyl ketone, methyl isobutyl ketone, ethanol, toluene, benzene, diethylether, methyl ethyl ether, water and the like.

A polymer precipitated by putting the reaction solution into the poorsolvent is recovered by filtration, and then may be dried at normal orreduced pressure and at normal temperature or by heating. By repeatingan operation for redissolving the precipitated, recovered polymer in anorganic solvent, followed by reprecipitating and recovering the polymertwo to ten times, impurities in the polymer may be reduced. In thiscase, examples of the poor solvent may include alcohols, ketones,hydrocarbons and the like. Use of three or more of the poor solventsselected therefrom is preferable because a purification efficiency isfurther increased.

As for a molecular weight of the component (A) according to the presentinvention, a weight average molecular weight determined by a gelpermeation chromatography (GPC) method may be preferably from 2000 to1000000, and more preferably from 5000 to 200000.

As described above, the photoreactive liquid crystal compositionaccording to the present invention may include other components otherthan the component (A) or (B).

Examples of the other components may include, depending on the component(A) and the component (B) used, application of the photoreactive liquidcrystal composition and the like, antioxidants such as hindered aminesor hindered phenols; polymerizable compounds each having aphotopolymerizable group or a photocrosslinkable group on one or moreterminals, and the like.

Specific examples of the polymerizable compounds may include, but arenot limited to, the following compounds, wherein V represents a singlebond or —R₈O—, preferably —R₈O—, wherein R₈ represents a linear orbranched alkylene group having 1 to 10, preferably 2 to 6 carbon atoms;W represents a single bond or OR₉—, preferably —OR₉—, wherein R₉represents a linear or branched alkylene group having 1 to 10,preferably 2 to 6 carbon atoms; V and W may have the same structure asor different structures from each other, but synthesis is easy when Vand W have the same structure; and R₇ represents H or an alkyl grouphaving 1 to 4 carbon atoms.

<Element Obtained by Photoreactive Liquid Crystal Composition and Methodfor Manufacturing the Same>

The present application also provides an element obtained by the abovephotoreactive liquid crystal composition and a method for manufacturingthe element.

The element according to the present invention comprises and is formedof a liquid crystal cell comprising the above photoreactive liquidcrystal composition.

Examples of the element may include a display element; an opticalelement such as a diffraction grating, a lens, a mirror or the like; orthe like.

The element, specifically a display element or an optical elementaccording to the present invention can be formed by filling the abovephotoreactive liquid crystal composition into a liquid crystal cell.

Specifically, the element according to the present invention can bemanufactured by the following steps:

[I] filling a photoreactive liquid crystal composition comprising (A) aphotoreactive polymer liquid crystal having a photoreactive side chain,which causes at least one reaction selected from the group consisting of(A-1) photocrosslinking and (A-2) photoisomerization; and (B) a lowmolecular liquid crystal; into a space formed between two transparentsubstrates disposed in parallel and apart from each other, to form aliquid crystal cell; and

[II] irradiating the liquid crystal cell obtained in the step [I] with apolarized ultraviolet ray from one of the two transparent substrates;

to form the element according to the present invention, specifically theelement having a predetermined orientation of the (B) low molecularliquid crystal in the liquid crystal cell.

The step [I] is a step of filling the above photoreactive liquid crystalcomposition into a space formed between two transparent substrates, inwhich at least one substrate on a side which is irradiated with anultraviolet ray is transparent, disposed in parallel and apart from eachother, to form a liquid crystal cell.

The liquid crystal cell has the space by disposing the two transparentsubstrates apart, from each other to some extent in parallel, and isformed by filling the above photoreactive composition into the space.

Examples of the substrate may include glass and a plastic such asacrylic resins, polycarbonates or the like. The substrate may haveflexibility depending on an element formed.

The substrate may comprise various films, for example, a film formed ofpolyvinyl alcohol, polyether, polyethylene, PET, polyamide, polyimide,an acrylic resin, polycarbonate, or polyurea on a side of the spacedepending on an element formed. For example, the film used herein mayexhibit the following effect. In order to induce a photoreaction of the(A) photoreactive polymer liquid crystal in the step [II] describedhereinafter, a molecular long axis of the (A) photoreactive polymerliquid crystal may be positioned horizontally in a surface of thesubstrate so as to absorb polarized light. On the other hand, since the(A) photoreactive polymer liquid crystal is encapsulated in the liquidcrystal cell as a composition with the (B) low molecular liquid crystal,in order to make the molecular long axis of the (A) photoreactivepolymer liquid crystal positioned horizontally in the surface of thesubstrate, the (B) low molecular liquid crystal may be also positionedhorizontally in the surface of the substrate. Therefore, the above filmmay be a film in which the molecular long axis of the photoreactivecomposition may be positioned horizontally in the surface of thesubstrate. A material of the film is not limited as long as the film issuch a film.

The step [II] is a step of irradiating the liquid crystal cell obtainedin the step [I] with a polarized ultraviolet ray. The polarizedultraviolet ray is emitted from an outside of one of the two transparentsubstrates. Therefore, as described above, the transparent substratesmay transmit a polarized ultraviolet ray.

A wavelength range of the polarized ultraviolet ray, depending on anelement formed, may be 100 nm to 400 nm. It is preferable to select anoptimal wavelength through a filter or the like according to the kind ofa coating film used. For example, an ultraviolet ray in a wavelengthrange of 290 nm to 400 nm can be selected to be used such that aphotocrosslinking reaction can be induced selectively. Examples of theultraviolet ray include light emitted from a high pressure mercury lamp.

By irradiating a first position of an optical element, and a secondposition, which is different from the first position, with differentpolarized ultraviolet rays, it is possible to form an element, forexample, an optical element, having the (B) low molecular liquid crystalwith different orientations between the first and second positions ofthe element.

Specifically, by irradiating the first position with a polarizedultraviolet ray having a first polarizing axis and irradiating thesecond position with a polarized ultraviolet ray having a secondpolarizing axis, which is different from the first polarizing axis, itis possible to form an element, for example, an optical element, havingthe (B) low molecular liquid crystal with different orientations betweenthe first and second positions of the element.

Further, for example, in a case where an element formed is a diffractiongrating, by being subject to interference exposure of a polarizedultraviolet ray to the liquid crystal cell, it is possible to form adiffraction grating which is an optical element having an orientationdistribution in which orientation is different depending on the positionof the element, specifically having an orientation distribution in whichorientation is periodically changed.

When a liquid crystal cell is irradiated with a polarized ultravioletray, it is considered that the following mechanism occurs in the liquidcrystal cell. The (A) photoreactive polymer liquid crystal in the liquidcrystal cell has orientation according to the polarized ultraviolet ray.

The (B) low molecular liquid crystal is oriented according to theorientation of the (A) photoreactive polymer liquid crystal.

The (A) photoreactive polymer liquid crystal and the (B) low molecularliquid crystal thereby have orientation according to the polarizedultraviolet ray.

For example, as described above, by being subject, to interferenceexposure to a polarized ultraviolet ray to the liquid crystal cell, the(A) photoreactive polymer liquid crystal has different orientationdepending on the position of an element, and in accordance therewith,the (B) low molecular liquid crystal also has different orientationdepending on the position of the element. Therefore, by being subject tointerference exposure to a polarized ultraviolet ray to the liquidcrystal cell, it is possible to form a diffraction grating which is anoptical element having an orientation distribution in which orientationis different depending on the position of the element, specificallyhaving an orientation distribution in which orientation is periodicallychanged.

EXAMPLES Example 1

One part by weight of a photoreactive polymer liquid crystal representedby formula PRP-1a was added to 99 parts by weight of4-n-pentyl-4′-cyanobiphenyl (5CB) which was a low molecular liquidcrystal. Then, the resulting mixture was stirred at 180° C. for 20minutes to obtain a photoreactive liquid crystal composition.

Then, the photoreactive liquid crystal composition was encapsulated in aparallel flat plate cell formed of two glass substrates having a 5 μmgap with an ITO on both inner surfaces of the substrate, to form aliquid crystal cell.

The resulting liquid crystal cell was subjected to polarizing hologramexposure to form a one-dimensional phase grating. The hologram exposurewas performed according to the optical path diagram illustrated in FIG.1 . In FIG. 1 , “HWP” indicates a half-wave plate, “QWP” indicates aquarter-wave plate, “M” indicates a mirror, and “PBS” indicates apolarization beam splitter.

Specifically, linearly polarized He-Cd laser light (0.47 W/cm²) having awavelength of 325 nm was used as an exposure light source. This laserbeam was divided into two light waves having an equal intensity by abeam splitter, and then a polarization state was confirmed with a waveplate. Then, interference was performed in the cell for 70 seconds. Eachof incident angles of the two light waves was ±0.75° (a grating pitchwas 12 μm). Furthermore, an incident surface of the two light waves wasreferred to as an xz-plane, and a normal vector to substrate and agrating vector were made parallel to a z-direction and an x-direction,respectively.

After the interference exposure, linearly polarized laser light having awavelength of 633 nm as a probe light was irradiated vertically to theliquid crystal cell, to determine an intensity of transmitteddiffraction light. FIG. 2 illustrates an optical path diagram for thedetermination. In FIG. 2 , “HWP” and “QWP” have been described above,“GP” indicates a Glan-Thompson prism, and “PD” indicates aphotodetector. Specifically, a homogeneous orientation cell having acell thickness of 5 μm was disposed such that a director was parallel tothe y-axis. A diffraction efficiency (intensity ratio between diffractedlight and incident light) in +1 order diffraction when a grating wasrecorded by interference of two light waves in s-polarized light wasdetermined.

FIGS. 3 and 4 illustrate measurement results thereof.

FIG. 3 illustrates the diffraction efficiency depending on polarizationazimuth of the probe linearly polarized light (the x-direction is 0° andthe y-direction is 90°). FIG. 3 shows that the diffraction efficiencylargely depends on a polarization state of incident light, suggestingthat anisotropic refractive index modulation has been formed in thecell.

FIG. 4 illustrates results of the diffraction efficiency when arectangular voltage of 1 kHz was applied (when a voltage was increased).It is confirmed from FIG. 4 that the diffraction efficiency can becontrolled by application of a voltage.

Comparative Example 1

Hologram recording was performed in a manner similar to Example 1 exceptthat the liquid crystal composition encapsulated in the parallel flatplate cell was only 5CB, to determine an intensity of transmitteddiffraction light. As a result, a diffraction phenomenon was notobserved in probe linearly polarized light in any condition.

Example 1 and Comparative Example 1 show that the liquid crystalcomposition according to the present invention, i.e., the liquid crystalcomposition in Example 1 including the (A) photoreactive polymer liquidcrystal and the (B) low molecular liquid crystal has photoreactivity,but the liquid crystal composition in Comparative Example 1 does notexhibit photoreactivity. Further, it has been found that a diffractiongrating can be manufactured by using the liquid crystal composition inExample 1.

What is claimed is:
 1. A photoreactive liquid crystal compositioncomprising: (A) a photoreactive polymer liquid crystal having aphotoreactive side chain, which reacts by at least one reaction selectedfrom the group consisting of (A-1) photocrosslinking, and (A-2)photoisomerization; and (B) a low molecular liquid crystal, wherein the(A) photoreactive polymer liquid crystal comprises a rigid mesogeniccomponent, wherein the (A) photoreactive polymer liquid crystalcomprises any one photoreactive side chain selected from the groupconsisting of the following formulae (11) to (13):

wherein A independently represents a single bond, —O—, —CH₂—, —COO—,—OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; B represents —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; Xrepresents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different; l represents an integer of 1 to12, m represents an integer of 0 to 2, and m1 represents an integer of 1to 3; and R represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six rings selected therefrom are bonded through abonding group B, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ wherein R₀ represents a hydrogen atomor an alkyl group having 1 to 5 carbon atoms, —NO₂, —CN, —CH═C(CN)₂,—CH═CH—CN, a halogen group, an alkyl group having 1 to 5 carbon atoms,or an alkyloxy group having 1 to 5 carbon atoms, a hydroxy group, or analkoxy group having 1 to 6 carbon atoms.
 2. The composition according toclaim 1, wherein the (A) photoreactive polymer liquid crystal comprisesa photoreactive side chain, which reacts by the (A-1) photocrosslinkingreaction.
 3. The composition according to claim 1, wherein a weightratio of the (A) photoreactive polymer liquid crystal and the (B) lowmolecular liquid crystal is 0.1:99.9 to 20:80.
 4. A display elementcomprising a liquid crystal cell comprising the photoreactive liquidcrystal composition according to claim
 1. 5. A display elementcomprising a liquid crystal cell comprising the photoreactive liquidcrystal composition according to claim 1, wherein the (B) low molecularliquid crystal has predetermined orientation in the liquid crystal cell.6. An optical element comprising a liquid crystal comprising thephotoreactive liquid crystal composition according to claim
 1. 7. Anoptical element comprising a liquid crystal cell comprising thephotoreactive liquid crystal composition according to claim 1, whereinthe (B) low molecular liquid crystal has predetermined orientation inthe liquid crystal cell.
 8. The optical element according to claim 7,wherein the predetermined orientation has an orientation distribution inwhich orientation is different depending on the position of the opticalelement.
 9. A method for manufacturing an optical element, comprising:[I] filling a photoreactive liquid crystal composition comprising (A) aphotoreactive polymer liquid crystal having a photoreactive side chain,which reacts by at least one reaction selected from the group consistingof (A-1) photocrosslinking and (A-2) photoisomerization, and (B) a lowmolecular liquid crystal into a space formed between two transparentsubstrates disposed in parallel and apart from each other, to form aliquid crystal cell; and [II] irradiating the liquid crystal cell with apolarized ultraviolet ray from one of the two transparent substrates, toform the optical element having a predetermined orientation of the (B)low molecular liquid crystal in the liquid crystal cell, wherein the (A)photoreactive polymer liquid crystal comprises any one photoreactiveside chain selected from the Croup consisting of the following formulae(11) to (13):

wherein A independently represents a single bond, —O—, —CH₂—, —COO—,—OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; B represents —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; Xrepresents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different; l represents an integer of 1 to12, m represents an integer of 0 to 2, and m1 represents an integer of 1to 3; and R represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six rings selected therefrom are bonded through abonding group B, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ wherein R₀ represents a hydrogen atomor an alkyl group having 1 to 5 carbon atoms, —NO₂, —CN, —CH═C(CN)₂,—CH═CH—CN, a halogen group, an alkyl group having 1 to 5 carbon atoms,or an alkyloxy group having 1 to 5 carbon atoms, a hydroxy group, or analkoxy group having 1 to 6 carbon atoms.
 10. The method according toclaim 9, wherein the irradiating [II] comprises: setting a polarizingaxis of a polarized ultraviolet ray with respect to a first position ofthe optical element as a first axis; and setting a polarizing axis of apolarized ultraviolet ray with respect to a second position, which isdifferent from the first position of the optical element, as a secondaxis, which is different from the first axis, to form the opticalelement having the (B) low molecular liquid crystal with differentorientations between the first and second positions of the opticalelement.
 11. The method according to claim 9, wherein, the irradiating[II] comprises: subjecting the liquid crystal cell to interferenceexposure of the polarized ultraviolet ray, the predetermined orientationhaving an orientation distribution in which orientation is differentdepending on the position of the optical element.
 12. A method formanufacturing a display element, comprising: [I] filling a photoreactiveliquid crystal composition comprising (A) a photoreactive polymer liquidcrystal having a photoreactive side chain, which reacts by at least onereaction selected from the group consisting of (A-1) photocrosslinkingand (A-2) photoisomerization, and (B) a low molecular liquid crystalinto a space formed between two transparent substrates disposed inparallel and apart from each other, to form a liquid crystal cell; and[II] irradiating the liquid crystal cell with a polarized ultravioletray from one of the two transparent substrates, to form the displayelement having a predetermined orientation of the (B) low molecularliquid crystal in the liquid crystal cell, wherein the (A) photoreactivepolymer liquid crystal comprises any one photoreactive side chainselected from the group consisting of the following formulae (11) to(13):

wherein A independently represents a single bond, —O—, —CH₂—, —COO—,—OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; B represents —O—,—CH₂—, —COO—, —OCO—, —CONH—, —NH—CO—, —CH═CH—CO—O—, or —O—CO—CH═CH—; Xrepresents a single bond, —COO—, —OCO—, —N═N—, —CH═CH—, —C≡C—,—CH═CH—CO—O—, or —O—CO—CH═CH—, and in a case where the number of X is 2,these Xs may be the same or different; l represents an integer of 1 to12, m represents an integer of 0 to 2, and m1 represents an integer of 1to 3; and R represents a ring selected from a monovalent benzene ring, amonovalent naphthalene ring, a monovalent biphenyl ring, a monovalentfuran ring, a monovalent pyrrole ring and a monovalent alicyclichydrocarbon having 5 to 8 carbon atoms, or a group in which the same ordifferent two to six rings selected therefrom are bonded through abonding group B, wherein a hydrogen atom bonded thereto may be eachindependently replaced with —COOR₀ wherein R₀ represents a hydrogen atomor an alkyl group having 1 to 5 carbon atoms, —NO₂, —CN, —CH═C(CN)₂,—CH═CH—CN, a halogen group, an alkyl group having 1 to 5 carbon atoms,or an alkyloxy group having 1 to 5 carbon atoms, a hydroxy group, or analkoxy group having 1 to 6 carbon atoms.
 13. The photoreactive liquidcrystal composition according to claim 1, wherein the (A) photoreactivepolymer liquid crystal has at least one selected from the followingcharacteristics i) to iv) i) the (A) photoreactive polymer liquidcrystal is a polymer exhibiting liquid crystalline property in apredetermined temperature range and having a photoreactive side chain,ii) the (A) photoreactive polymer liquid crystal reacts by light in awavelength range of 250 nm to 400 nm and exhibits liquid crystallineproperty in a temperature range of 50 to 300° C., iii) the (A)photoreactive polymer liquid crystal has a photoreactive side chain toreact with light in a wavelength range of 250 run to 400 nm, and/or iv)the (A) photoreactive polymer liquid crystal iv) has a mesogenic groupin order to exhibit liquid crystalline property in a temperature rangeof 50 to 300° C.